Chemistry. a mechanically separate, homogeneous part of a heterogeneous system: the solid, liquid, and gaseous phases of a system.

Physics. a particular stage or point of advancement in a cycle; the fractional part of the period through which the time has advanced, measured from some arbitrary origin often expressed as an angle (phase angle), the entire period being taken as 360°.

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verb (used with object),phased,phas·ing.

to schedule or order so as to be available when or as needed.

to put in phase; synchronize: to phase one mechanism with another.

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Verb Phrases

phase down, to reduce by gradual stages.

phase in, to put or come into use gradually; incorporate by degrees: to phase in new machinery.

phase out, to bring or come to an end gradually; ease out of service: to phase out obsolescent machinery.

phase in

(tr, adverb)to introduce in a gradual or cautious mannerthe legislation will be phased in over two years

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phase

noun

any distinct or characteristic period or stage in a sequence of events or chain of developmentthere were two phases to the resolution; his immaturity was a passing phase

astronomyone of the recurring shapes of the portion of the moon or an inferior planet illuminated by the sunthe new moon, first quarter, full moon, and last quarter are the four principal phases of the moon

physics

the fraction of a cycle of a periodic quantity that has been completed at a specific reference time, expressed as an angle

(as modifier)a phase shift

physicsa particular stage in a periodic process or phenomenon

in phase(of two waveforms) reaching corresponding phases at the same time

out of phase(of two waveforms) not in phase

chema distinct state of matter characterized by homogeneous composition and properties and the possession of a clearly defined boundary

zoologya variation in the normal form of an animal, esp a colour variation, brought about by seasonal or geographical change

biology(usually in combination)a stage in mitosis or meiosisprophase; metaphase

electrical engineeringone of the circuits in a system in which there are two or more alternating voltages displaced by equal amounts in phase (sense 5)See also polyphase (def. 1)

(in systemic grammar) the type of correspondence that exists between the predicators in a clause that has two or more predicators; for example connection by to, as in I managed to do it, or -ing, as in we heard him singing

(sometimes foll by with)to cause (a part, process, etc) to function or coincide with (another part, process, etc)he tried to phase the intake and output of the machine; he phased the intake with the output

mainlyUSto arrange (processes, goods, etc) to be supplied or executed when required

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Derived Formsphaseless, adjectivephasicorphaseal, adjective

Word Origin

C19: from New Latin phases, pl of phasis, from Greek: aspect; related to Greek phainein to show

Word Origin and History for phase in

phase

n.

1705, "phase of the moon," back-formed as a singular from Modern Latin phases, plural of phasis, from Greek phasis "appearance" (of a star), "phase" (of the moon), from stem of phainein "to show, to make appear" (see phantasm). Latin singular phasis was used in English from 1660. Non-lunar application is first attested 1841. Meaning "temporary difficult period" (especially of adolescents) is attested from 1913.

phase

[fāz]

Any of the forms, recurring in cycles, in which the Moon or a planet appears in the sky.

One of a set of possible homogenous, discrete states of a physical system. States of matter such as solid and liquid are examples of phases, as are different crystal lattice structures in metals such as iron. See also phase transitionstate of matter.

A measure of how far some cyclic behavior, such as wave motion, has proceeded through its cycle, measured in degrees or radians. At the beginning of the phase, its value is zero; at one quarter of its cycle, its phase is 90 degrees (π/2 radians); halfway through the cycle its value is 180 degrees (π radians), and so on.♦ The phase angle between two waves is a measure of their difference in phase. Two waves of the same frequency that are perfectly in phase have phase angle zero; if one wave is ahead of the other by a quarter cycle, its phase angle 90 degrees (π/2 radians); waves that are perfectly out of phase have phase angle 180 degrees (π radians), and so on. See more at wave.

Idioms and Phrases with phase in

phase in

Introduce one stage at a time. For example, New technology must be phased in or the office will be overwhelmed. The antonym is phase out, meaning “to bring or come to an end, one stage at a time,” as in The department is phasing out all the older computers. [Mid-1900s]